The semiconductor integrated circuit industry has experienced rapid growth in the past several decades. Technological advances in semiconductor materials and design have produced increasingly smaller and more complex circuits. These material and design advances have been made possible as the technologies related to processing and manufacturing have also undergone technical advances. In the course of semiconductor evolution, the number of interconnected devices per unit of area has increased as the size of the smallest component that can be reliably created has decreased.
Metal-insulator-metal (MiM) capacitors are used in many applications on an integrated circuit (IC), including for signal conditioning. During the operation of certain circuits, power supply lines may supply transient currents with a relatively high intensity. These conditions can result in noise on the power supply lines. Specifically, the voltage on the power supply line may fluctuate when the transition time of the transient current is particularly short or when the line's parasitic inductance or parasitic resistance is large. To ameliorate such conditions, filtering or decoupling capacitors may be used, acting as temporary charge reservoirs to prevent momentary fluctuations in supply voltage.
Integrating decoupling capacitors into certain systems-on-chip (SOCs) may entail a number of problems. For example, some decoupling capacitors may suffer from capacitance variations, delamination of conductors from the electrodes, or inadequate electrical coupling between the conductor and the electrodes. These capacitors may be integrated in the multi-level interconnect (MLI) at different levels. Before circuit design and a process for forming a circuit can be qualified for manufacturing, all devices including MiM capacitors should be tested to verify functionality.
The various features disclosed in the drawings briefly described above will become more apparent to one of skill in the art upon reading the detailed description below. Where features depicted in the various figures are common between two or more figures, the same identifying numerals have been used for clarity of description.